The threat of a paedophile ring operating in parts of Donegal was not being properly monitored by social workers, watchdogs have warned.

An inspection of child protection in the county last May uncovered a lack of staff and glaring gaps in how the risks to children from institutional or organised abuse were managed.

Social work staff - part of the Tusla Child and Family Agency since January - had limited resources and used inadequate systems to identify potential abusers in the area.

The review, by the Health Information and Quality Authority (Hiqa), found good efforts were made to manage the risks posed by convicted and alleged offenders, but that the systems were not robust or safe enough.

"This included systems to identify potential organised abuse in the locality," the Hiqa report found.

Inspectors found minimal contact between social workers and probation officers, and the assessment service to monitor suspect adults had a waiting list because of a lack of resources.

Hiqa said there was a six-month delay to assess one convicted offender.

Inspectors reviewed a number of adult cases awaiting an assessment and reported that the immediate risk to children was not known at the time.

Hiqa found that one case did not show that potential organised abuse was considered.

The agency said its inspectors immediately moved to improve this failing and called on social services to review the case, and plan to examine all cases on waiting lists to identify and manage risks to children.

The Hiqa review involved an examination of 120 children's case files.

It noted that the Child Protection Notification System was not available on a 24-hour basis for gardai or other authorities.

Fifteen children were on alert in May and subsequently all got social workers, Hiqa said.

The review also warned that meetings with gardai on suspect abusers focused on individuals and not the potential for organised abuse or paedophile rings.

"Although efforts were made to identify, assess and manage risks posed by alleged or convicted offenders in the community, early warning systems to identify organised abuse were not robust enough," the report found.

"Delayed risk assessments meant that immediate risks to children may not have been identified and managed by the service."

In March 2014 a total of 169 child protection cases were awaiting allocation to a social worker.

"Team leaders told inspectors that they were not confident that all children had been visited while awaiting a social work service and acknowledged that these cases were not effectively monitored and that children's needs went unmet or unidentified. This was confirmed in cases reviewed by inspectors," the report said.

Inspectors met with eight children and young people and held meetings or telephone interviews with five parents, 13 social workers, and other team leaders and gardai during the review.

Overall the Tusla services complied with only five of the 27 standards in the Children First guidelines.

Donegal had 79 children on the Child Protection Notification System (CPNS) at the time of the inspection.

Tusla said the report offered a chance to improve.

Brian Lee, director of quality assurance with the agency, said: "The inspections process provides a useful, independent perspective of what we are doing well and an opportunity to improve our services. I am pleased that the final report recognises the service's many positive achievements and the dedication of its local staff, with no major risks identified.

"A comprehensive action plan is being implemented to address the findings of the report."